Apparatus for separating oxygen from air and delivering the oxygen under pressure



Oct. 11, 1938. A. MESSER 2,133,105

APPARATUS FOR SEPARATING OXYGEN FROM AIR AND DELIVERING THE OXYGEN UNDER PRESSURE Filed Oct. 17, 1956 IINVENTOR 40 09 Messer ATTORNEYS Patented Oct. 11, 1938 UNITED STATES APPARATUS FOR SEPARATING OXYGEN FROM AIR AND DELIVERING THE OXY- GEN UNDER PRESSURE Adolf Messer, Frankfort-on-the-Main, Germany Application October 17, 1936, Serial No. 106,166

- In Germany September 4, 1936 4 Claims.

For drawing the separated liquid oxygen under low pressure from an air separating plant and delivering it to a high pressure, for instance through an evaporating coil, a pump of the 5 plunger type immersed in a body of liquid oxygen collected ina portion of the separating apparatus, is not satisfactory. The heat produced by the sliding friction of the plunger along the cylinder walls, and the vacuum produced in the cylinder, give rise to fractional evaporation or distillation of the liquid oxygen in the cylinder and impairs the efliciency.

To cool down the liquid oxygen to avoid any evaporation in the pump cylinder while the liquid oxygen is being drawn into the pump, is a.

very expensive and complicated process.

One object of the present invention is to provide an apparatus which is efiicient in operation and does not have the disadvantages, above referred to.

In carrying out the present invention in its preferred form, there is provided a slow running gear pump for raising the liquid oxygen against pressure. This gear pump has no slid- 35 ing parts which will create sufficient friction to evaporate the liquid oxygen, and creates no vacuum which might impair the eflicient operation of the pump.

As a feature of the present invention, the main 30 drive shaft of the gear pumpis inclined, upwardly from the pump with respect to the horizontal, and the stufiing box for the main drive shaft and the driving motor are disposed in the relatively warm outside atmosphere. This in- 35 clination of the main drive shaft is preferably such that the stufling box will be near the maximum level of the liquid oxygen in the air separating column, so that there is little or no pressure of the liquid oxygen acting on said stuffing 40 box. Furthermore, by providing an inclined shaft, any liquid oxygen evaporated along the shaft will rise to the level of the stufiing box and will act somewhat as an insulation against heat conduction from the outside atmosphere, 5 and prevent-the inflow of further liquid oxygen.

As a further feature, there is provided a variable speed transmission between the motor and the drive shaft, whereby the speed of the pump may be regulated in accordance with the quan- 59 tity and pressure desired in the liquid oxygen.

Since the motor, the variable speed transmission, and the stufiing box for the main drive shaft, are disposed away from the cold region of the separating apparatus and in the warm 55 outside atmosphere, the lubricating agents thereon will not be cooled sufficiently to impair the function of these pump operating members.

In the accompanying drawing, there is shown for the purpose of illustration, one form of air separating apparatus embodying the present 5 invention.

In this drawing there is shown a column Ill having a heat interchanger II at the upper end, and a rectifying section 12 at the lower end. Air-under pressure is delivered through a coil 10 I3 of the heat interchanger H where it passes in countercurrent heat interchange relationship with the outfiowing nitrogen .and a coil l4 in which the evaporation of the separated liquid oxygen takes place. The precooled air leaving 16 the interchanger ll goes through a coil l5 at the bottom of the column In throgh an expansion valve l6, and is delivered at the upper end of a series of trays I! in the rectifying section I2 of the column. By this operation, as the 20 resulting liquefied air trinkles downwardly over the trays [1, it is separated into the liquid oxygen which collects at the bottom of the column l0, and gaseous nitrogen which passes around the coils of the heat interchanger I l and out through an outlet la. The coil I4 is provided with a valved outlet l9 which delivers the separated evaporated oxygen to a suitable storage tank at a substantial pressure controlled by the adjustment of the valve 20 in said outlet, without the necessity of compressing said evaporated oxygen.

As a feature of the present invention, the liquid oxygen collected at the bottom of column [0 is delivered to the inlet end of the coil l4 in the heat interchanger H through a gear pump 2| having an inlet 22 and an outlet 23, the two gear members of the pump being operated at low speed through a gear arrangement, such as a worm and worm wheel, from a main drive shaft 24. This shaft 24 is encircled by a tubing or sheathing 25 which slants upwardly and outwardly as shown.

The shaft 24 is operated from an electric motor 26 and the speed of rotation of said shaft is controlled by a variable speed transmission 28 which may be adjusted by a suitable control handle 30. i The shaft 24 is supported by a hearing which is mounted outside the cold region of the separating apparatus so as to be in contact with the warm outside air, said bearing comprising or including a stuffing box 32 to prevent leakage of oxygen therethrough. The stufiing box and the shaft 24 are preferably so arranged that the stufiing box will be at substantially the maximum level of the liquid oxygen in the bottom of the column ll, so that the liquid oxygen in the tubing acts with little or no pressure on said stufiing box. Furthermore, by means of this arrangement, any evaporated oxygen will rise along the shaft 24 and be trapped at the upper end thereof so as to serve as a heat insulation to prevent the conduction of heat into the main body of the liquid oxygen and prevent liquid oxygen from flowingup to the stufllng box.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. An apparatus for separating oxygen from air, which includes a rectification column in the bottom of which the liquid oxygen separates and collects, a liquid oxygen evaporating coil, a pump in the bottom of said column for forcing the separated liquid oxygen through said evaporating coil, and having a drive shaft extending to the exterior of the apparatus, a easingencircling said shaft, and a stuffing box disposed at the outer end of said casing outside the cold region of the column and in the warmer outside atmosphere.

2. An apparatus for separating oxygen from air, which includes a rectification column in the bottom of which the liquid oxygen separates and collects, a liquid oxygen evaporating coil, a pump in the bottom of said column for forcing the separated liquid oxygen through said evaporating coil, and a main drive shaft for driving said pump and slanting upwardly and outwardly fromthe latter.

An apparatus for separating oxygen from air, which includes a rectification column in the bottom of which the liquid oxygen separates and collects, a liquid oxygen evaporating coil, a gear pump in the bottom of said column for forcing the separated liquid oxygen through said evaporating coil, a main drive shaft for driving said gear pump and slanting upwardly and outwardly from the latter, a motor for driving said shaft, and a stuffing box for said main drive shaft, said motor and said stufllng box being disposed outside of the cold region of the column and in the warmer outside atmosphere.

4. An apparatus for separating oxygen from air, which includes a rectification column in the bottom of which the oxygen separates in liquid form, a heat interchanger including an oxygen evaporating coil having an outlet leading to a storage holder, a rotary pump at the bottom of said colunm for forcing the separated liquid oxygen through said evaporating coil, a shaft extending upwardly and outwardly from said pump, a tubular casing encircling said shaft and open at the lower end, and a stumng box at the outer upper end for trapping gaseous oxygen in said casing.

ADOLF MESSER. 

